U.S. patent number 9,244,003 [Application Number 14/620,807] was granted by the patent office on 2016-01-26 for alignment flange mounted optical window for a laser gas analyzer.
This patent grant is currently assigned to YOKOGAWA ELECTRIC CORPORATION. The grantee listed for this patent is YOKOGAWA ELECTRIC CORPORATION. Invention is credited to Alan I. Cowie, Junichi Matsuo.
United States Patent |
9,244,003 |
Matsuo , et al. |
January 26, 2016 |
Alignment flange mounted optical window for a laser gas
analyzer
Abstract
An alignment unit for a laser analyzer that performs
measurements on a substance inside a chamber includes a first
alignment flange that attaches to the chamber, a second alignment
flange that attaches one of a launch unit or detect unit of the
laser analyzer to the chamber, an alignment stud for adjusting
horizontal and vertical alignment of the second alignment flange,
an optical window that keeps the chamber closed when the one of the
launch unit or detect unit is removed from the chamber, and a
sealing member provided between the second alignment flange and the
optical window.
Inventors: |
Matsuo; Junichi (Tokyo,
JP), Cowie; Alan I. (Friendswood, TX) |
Applicant: |
Name |
City |
State |
Country |
Type |
YOKOGAWA ELECTRIC CORPORATION |
Tokyo |
N/A |
JP |
|
|
Assignee: |
YOKOGAWA ELECTRIC CORPORATION
(Tokyo, JP)
|
Family
ID: |
55086078 |
Appl.
No.: |
14/620,807 |
Filed: |
February 12, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01N
21/39 (20130101); G01N 21/0303 (20130101); G01N
21/05 (20130101); G01N 2201/02 (20130101); G01N
2201/0612 (20130101); G01N 21/3504 (20130101) |
Current International
Class: |
G01N
21/00 (20060101); G01N 21/39 (20060101); G01N
21/31 (20060101); G01N 21/27 (20060101) |
Field of
Search: |
;356/244,246,432-440
;422/83,88,89 ;250/573,574,576 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
5336394 |
|
Nov 2013 |
|
JP |
|
5440524 |
|
Mar 2014 |
|
JP |
|
Primary Examiner: Pham; Hoa
Attorney, Agent or Firm: Osha Liang LLP
Claims
What is claimed is:
1. A laser analyzer for performing measurements on a substance
inside a chamber, comprising: a launch unit comprising a diode
laser that irradiates the substance with laser light; a detect unit
comprising a light receiving element that detects the laser light
having passed through the substance; and an alignment unit for
removably connecting one of the launch unit or detect unit to the
chamber, wherein the alignment unit comprises: a first alignment
flange that attaches to the chamber; a second alignment flange that
attaches to the one of the launch unit or detect unit; an alignment
stud for adjusting horizontal and vertical alignment of the second
alignment flange; an optical window that keeps the chamber closed
when the one of the launch unit or detect unit is removed from the
chamber; and a sealing member provided between the second alignment
flange and the optical window.
2. The laser analyzer of claim 1, wherein the optical window is
angled relative to laser emission from the launch unit.
3. The laser analyzer of claim 1, wherein the one of the launch
unit or detect unit further comprises a quick connect plate, and
the alignment unit further comprises a quick connect screw that
hooks into the quick connect plate.
4. The laser analyzer of claim 3, wherein the quick connect plate
comprises: a hook slot, wherein the quick connect screw of the
alignment unit hooks into the hook slot when the one of the launch
unit or detect unit is connected to the alignment unit.
5. The laser analyzer of claim 1, further comprising: a second
alignment unit comprising: a first alignment flange that attaches
to the chamber; a second alignment flange that attaches to the
other of the launch unit or detect unit; an alignment stud for
adjusting horizontal and vertical alignment of the second alignment
flange; an optical window that keeps the chamber closed when the
other of the launch unit or detect unit is removed from the
chamber; and a sealing member provided between the second alignment
flange and the optical window.
6. The laser analyzer of claim 5, wherein the other of the launch
unit or detect unit comprises a quick connect plate, and the second
alignment unit further comprises a quick connect screw that hooks
onto the quick connect plate.
7. The laser analyzer of claim 6, wherein the second quick connect
plate is different from the quick connect plate.
8. The laser analyzer of claim 6, wherein the second quick connect
plate comprises: a hook slot, wherein the quick connect screw of
the second alignment unit hooks into the hook slot of the second
quick connect plate when the other of the launch unit or detect
unit is connected to the second alignment unit.
9. An alignment unit for a laser analyzer that performs
measurements on a substance inside a chamber and that comprises a
launch unit and a detect unit, the alignment unit comprising: a
first alignment flange that attaches to the chamber; a second
alignment flange that attaches one of the launch unit or detect
unit to the chamber; an alignment stud for adjusting horizontal and
vertical alignment of the second alignment flange; an optical
window that keeps the chamber closed when the one of the launch
unit or detect unit is removed from the chamber; and a sealing
member provided between the second alignment flange and the optical
window.
10. The alignment unit of claim 9, wherein the optical window is
angled relative to laser emission from the launch unit.
11. The alignment unit of claim 9, further comprising a quick
connect screw that hooks into a hook slot on a quick connect plate
on the one of the launch unit or detect unit when the one of the
launch unit or detect unit is connected to the alignment unit.
12. A laser analyzer system for performing measurements on a
substance inside a chamber, comprising: a modular launch unit
comprising a diode laser that irradiates the substance with laser
light; a modular detect unit comprising a light receiving element
that detects the laser light having passed through the substance;
an alignment unit for removably connecting one of the launch unit
or detect unit to the chamber, wherein the alignment unit
comprises: a first alignment flange that attaches to the chamber; a
second alignment flange that attaches to the one of the launch unit
or detect unit; an alignment stud for adjusting horizontal and
vertical alignment of the second alignment flange; an optical
window that keeps the chamber closed when the one of the launch
unit or detect unit is removed from the chamber; and a sealing
member provided between the second alignment flange and the optical
window.
13. The laser analyzer system of claim 12, wherein the optical
window is angled relative to laser emission from the launch
unit.
14. The laser analyzer system of claim 12, where the one of the
launch unit or detect unit further comprises a quick connect plate,
and the alignment unit further comprises a quick connect screw that
hooks into the quick connect plate.
15. The laser analyzer system of claim 14, wherein the quick
connect plate comprises: a hook slot, wherein the quick connect
screw of the alignment unit hooks into the hook slot when the one
of the launch unit or detect unit is connected to the alignment
unit.
16. The laser analyzer system of claim 12, further comprising: a
second alignment unit comprising: a first alignment flange that
attaches to the chamber; a second alignment flange that attaches to
the other of the launch unit or detect unit; an alignment stud for
adjusting horizontal and vertical alignment of the second alignment
flange; an optical window that keeps the chamber closed when the
other of the launch unit or detect unit is removed from the
chamber; and a sealing member provided between the second alignment
flange and the optical window.
17. The laser analyzer system of claim 16, wherein the other of the
launch unit or detect unit comprises a second quick connect plate,
and the second alignment unit further comprises a quick connect
screw that hooks onto the quick connect plate.
18. The laser analyzer system of claim 17, wherein the second quick
connect plate is different from the quick connect plate.
19. The laser analyzer system of claim 17, wherein the second quick
connect plate comprises: a hook slot, wherein the quick connect
screw of the second alignment unit hooks into the hook slot of the
second quick connect plate when the other of the launch unit or
detect unit is connected to the second alignment unit.
Description
FIELD OF DISCLOSURE
The present disclosure relates to a laser gas analyzer. In
particular, embodiments of the invention relate to an alignment
flange mounted optical window for a laser gas analyzer.
BACKGROUND
Laser analyzers are capable of determining the presence and/or
concentration of components in a gas or liquid medium. Laser gas
analyzers may use tunable diode laser absorption spectroscopy to
measure the concentration of a high-temperature component, a
component containing a corrosive gas, toxic gas, or the like. Such
laser gas analyzers may operate by irradiating the component to be
measured with light from a tunable diode laser with high component
selectivity, in a non-contact manner, at high speed, and in real
time without being subject to interference of other components.
Laser analyzers typically include a laser light source and a
detector. The laser light source typically irradiates, for example,
an atmosphere of a gas to be measured with measuring laser light.
The detector detects the measuring laser light that has passed
through the measuring space of the atmosphere of the gas to be
measured. The laser gas analyzer measures an inherent light
absorption spectrum of molecules, ranging from an infrared region
to a near infrared region, by using a diode laser in which the
emission wavelength spectral line width is extremely narrow. The
molecule-inherent light absorption spectrum may correspond to
molecule vibrations or rotation energy transitions. Inherent
absorption spectra of many molecules including O.sub.2, NH.sub.3,
H.sub.2O, CO, and CO.sub.2 are in the infrared to near infrared
regions of the electromagnetic spectrum. The concentration of the
target component may be calculated by determining the absorbed
amount (absorbance) of light at a specific wavelength.
Laser gas analyzers may use a peak height method, 2f method,
spectral area method or the like. For example, according to the
peak height method, the concentration of a component to be measured
is determined from the peak height of an absorption spectrum. In
the 2f method, a wavelength signal for scanning is modulated to
obtain a modulated waveform having a frequency twice the frequency
of the wavelength signal. Then, the concentration of a component to
be measured is determined based on a P-P (peak to peak) value of
the modulated waveform. In the spectral area method, the absorption
spectrum is measured while the emission wavelength of the laser is
scanned to obtain the spectral area. The component concentrations
may be calculated based on the spectral area. Unlike the other
methods, the spectral area method may not be affected by variations
of the pressure or coexisting gas components.
SUMMARY OF DISCLOSURE
In one aspect, according to one or more embodiments of the
invention, a laser analyzer for performing measurements on a
substance inside a chamber. The laser analyzer includes a launch
unit with a diode laser that irradiates the substance with laser
light, a detect unit with a light receiving element that detects
the laser light having passed through the substance, and an
alignment unit for removably connecting the launch unit or detect
unit to the chamber. The alignment unit includes a first alignment
flange that attaches to the chamber, a second alignment flange that
attaches to the one of the launch unit or detect unit, and an
alignment stud for adjusting horizontal and vertical alignment of
the second alignment flange. The alignment unit also includes an
optical window that keeps the chamber closed when the one of the
launch unit or detect unit is removed from the chamber and a
sealing member provided between the second alignment flange and the
optical window.
Other aspects of the invention will be apparent from the following
description and appended claims.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic of an alignment unit in accordance with one
or more embodiments of the invention.
FIG. 2A and FIG. 2B are schematics of an analyzer system in
accordance with one or more embodiments of the invention. FIG. 2A
is the analyzer system with the launch and detect units in
accordance with one or more embodiments of the invention. FIG. 2B
is the analyzer system without the launch and detect units in
accordance with one or more embodiments of the invention.
FIG. 3A is a schematic of a detect unit in accordance with one or
more embodiments of the invention. FIG. 3B is a schematic of a
quick connect plate in accordance with one or more embodiments of
the invention.
DETAILED DESCRIPTION
Specific embodiments of the invention will now be described in
detail with reference to the accompanying figures. Like elements in
the various figures are denoted by like reference numerals for
consistency.
In the following detailed description of embodiments of the
invention, numerous specific details are set forth in order to
provide a more thorough understanding of the invention. However, it
will be apparent to one of ordinary skill in the art that the
invention may be practiced without these specific details. In other
instances, well-known features have not been described in detail to
avoid unnecessarily complicating the description.
Embodiments of the invention relate to a laser analyzer, an
alignment unit for a laser analyzer, and a laser analyzing
system.
Generally, the principle of operation of a Tunable Diode Laser
Spectroscopy Analyzer is based on absorption spectroscopy. Such
analyzers may operate by measuring the amount of laser light that
is absorbed as it travels through the substance being measured. The
substance may include a gas or liquid.
One or more embodiments of the laser analyzer may include a launch
unit that includes a laser system and a detect unit that includes a
light receiving element, such as an optical detector. For example,
the launch unit may include a tunable diode laser where the
wavelength emission may be controlled based on the applied voltage
and/or temperature of the diode, as known in the art. The detect
unit may include a photodetector capable of detecting the light in
the wavelength region emitted by the launch unit. For example, for
near-infrared and infrared regions of the spectrum, an InGaAs
(indium gallium arsenide) based detector may be used.
The launch unit and detect unit are removably connectable to a
chamber containing the substance to be analyzed by the laser
analyzer. The chamber need not necessarily be a vacuum chamber and
may be a process pipe or vessel as known in the art. Both the
launch unit and detect unit may be connected or mounted separately
in accordance with one more embodiments of the invention. One or
more embodiments of the laser analyzer may include an alignment
unit to connect the detect unit to the chamber. One or more
embodiments of the laser analyzer may also include a second
alignment unit to connect the launch unit to the chamber. These
alignment units are designed to facilitate the alignment of the
laser through the chamber to optimize the signal in the detect unit
in accordance with one or more embodiments of the invention.
In previous models of laser gas analyzers, an optical window may be
included on the launch unit and detect unit to protect the laser or
detector, particularly with regard to the detector, from exposure
to the substance in the chamber, which may include a corrosive or
dirty process gas. Furthermore, in previous models of laser gas
analyzers, a valve was used on the alignment flange to prevent
leakage of the process gas by closing the valve prior to
calibration. However, in such systems, the substance in the chamber
may still be released or leaked during offline calibration,
maintenance, replacement or changing of the laser and detector, and
the like. Such systems typically include additional parts, such as
an inspection port, to attach to an alignment flange in place of
the laser system or detector. Other systems may include an
additional flange between the detector and the chamber that allows
the chamber to be closed off prior to removal of the unit.
One or more embodiments of the laser analyzer include an alignment
unit that includes an optical window. In one or more embodiments,
the optical window allows for inspection inside the chamber, while
preventing the substance from leaking out of the chamber. The
alignment unit may facilitate the removal, inspection, and/or
replacement of the launch and/or detect unit. In one or more
embodiments, the optical window may be mounted at an angle to avoid
direct reflection of the laser. For example, the optical window may
be mounted at approximately 3 degrees relative to the laser beam.
In one or more embodiments, the optical window may be used to
inspect the inside of the chamber containing the substance to be
interrogated.
In one or more embodiments of the invention, the alignment unit may
be mounted in place around the chamber such that the launch and
detect units are easily removable. Inspection through the optical
window may provide information such as measurement gas condition,
dust condition, and laser light characteristics emitted from launch
side. Such improvements allow the substance inside the chamber to
remain sealed, even if the detect unit and/or launch unit are
removed.
FIG. 1 is a schematic of an alignment unit (100) in accordance with
one or more embodiments of the invention. The alignment unit (100)
includes a first alignment flange (102) that attaches to a chamber
containing the substance to be interrogated by the analyzer. The
alignment unit (100) may also include a second alignment flange
(104) that attaches to the detect unit and/or launch unit. The
relative position of the second alignment flange (104) may be
adjusted using one or more alignment studs (106). As shown in FIG.
1, four alignment studs (106) may be used to adjust the relative
positions of the first (102) and second (104) alignment
flanges.
The second alignment flange (104) includes a window holder (108)
that houses an optical window (110). The window holder (108) may be
attached to the second alignment flange (104) by at least one screw
(112). In the example shown in FIG. 1, the window holder (108) is
attached to the second alignment flange (104) by at least three
screws (112) in accordance with one or more embodiments of the
invention. The screw (112) (or multiple screws) may be used to
mount the optical window to the second alignment flange (104) in
accordance with one or more embodiments of the invention.
One of ordinary skill in the art will appreciate that the window
holder may be optional, as the optical window (110) may be directly
incorporated into the second alignment flange (104).
The second alignment flange (104) of the alignment unit (100) may
also include one or more quick connect screws (114) for connecting
the alignment unit (100) to a quick connect plate of the detect
unit or launch unit. The quick connect screws will be explained in
more detail with respect to FIG. 3.
The second alignment flange (104) may also include a sealing member
(116) provided between the second alignment flange (104) and the
optical window (110), e.g., to secure a seal and prevent the
substance from leaking on the launch unit or detect unit. In the
example of FIG. 1, the sealing member (116) may include an O-ring
or the like to facilitate the seal between the second alignment
flange (104) and the optical window (110).
FIG. 2A and FIG. 2B are schematics of an analyzer system (200) in
accordance with one or more embodiments of the invention. FIG. 2A
demonstrates an analyzer system (200) that includes a launch unit
(220) and a detect unit (230) in accordance with one or more
embodiments of the invention. In the analyzer system (200), laser
light that is generated in the launch unit (220) passes through an
alignment unit (100) into a chamber (224) that contains the
substance (226) to be analyzed. The laser light continues through
the chamber (224) through the alignment unit (100) into the detect
unit (230) where it is evaluated. The detect unit (230) may be
connected to a computer system or processor (not shown) for the
evaluation.
FIG. 2B is the analyzer system (200) shown with the launch unit
(220) and the detect unit (230) removed from the system in
accordance with one or more embodiments of the invention. As
demonstrated in FIG. 2B, the launch unit (220) and/or the detect
unit (230) may be removed, for example, to use the optical window
(210) to inspect the inside of the chamber (224) or help
troubleshoot absorption measurements. Also, as demonstrated in the
example of FIG. 2B, the optical window (210) in the alignment unit
(100) keeps the chamber (224) closed, meaning the chamber is sealed
so that the substance (226) remains in the chamber (224).
The modular nature of the launch unit (220) and the detect unit
(230) may facilitate the use of different laser emitters and
detectors in the system in accordance with one or more embodiments
of the invention. For example, a launch unit (230) may be
characterized by the emission wavelength range emitted or the
specific laser diode used, and the modular nature of launch unit
may facilitate the changing of the wavelength range used to
interrogate the substance (226).
Such considerations are also true for the detect unit (230) in
accordance with one or more embodiments of the invention. For
example, different optical detectors have different regions of
sensitivity; therefore, the modular nature of the detect unit (230)
may allow for quickly and easily changing the detector unit (230)
in the system (200).
FIG. 3A is a schematic of a detect unit (330) in accordance with
one or more embodiments of the invention. The detect unit (330)
includes a quick connect plate (332) that connects the detect unit
(330) to the alignment unit (not shown in FIG. 3). The detect unit
(330) may also include one or more captive screws (334). For
example, as demonstrated in FIG. 3A, the captive screw (334) may be
permanently connected to the detect unit (330) to facilitate
locking down the connection of the detect unit (330) to the
alignment unit.
FIG. 3B is a schematic of the quick connect plate (332) in
accordance with one or more embodiments of the invention. As
demonstrated in the example of FIG. 3B, the quick connect plate
(332) includes a captive screw hole (336) to accommodate the
captive screw (334) in accordance with one or more embodiments of
the invention. The quick connect plate (332) may also include one
or more hook slots (338). The hook slots (338) are designed to hook
on to the one or more quick connect screws (114) shown in FIG. 1.
For example, the detect unit (330) is connected to the alignment
unit (100) by aligning the one or more quick connect screws (114)
shown in FIG. 1 to the one or more hook slots (338) shown in FIG.
3B, and rotating the detect unit (330) to lock the one or more
quick connect screws (114) into the hook locks (338). The detect
unit (330) may then be locked in place by tightening the captive
screw (334).
FIG. 3B shows three quick connect screws (114) and three hook slots
(338), forming a square shape that includes the captive screw hole
(336); however, embodiments of the invention are not limited to
such. For example, the pattern of the one or more quick connect
screws (114) and the quick one or more hook slots (338) may be
specifically selected to allow the connection of certain different
detect and/or launch units. In some embodiments, the aforementioned
pattern may be different for a connection between a detect unit and
an alignment unit as compared to a connection between a launch unit
and an alignment unit. In other embodiments, the pattern may be the
same for both connections.
One of ordinary skill in the art will appreciate that the
connection mechanism of the detect unit (330) described above with
respect to FIG. 3A and FIG. 3B may also be applied to the launch
unit in accordance with one or more embodiments.
One or more embodiments of the invention advantageously provide an
alignment unit that facilitates the removal/replacement of a detect
unit without the exposure of the substance to be measured. One or
more embodiments of the claimed invention advantageously provide an
optical window in an alignment unit for observation into the system
for various reasons, such as maintenance or alignment. With regard
to maintenance, the optical window may allow a user to determine if
any maintenance is required, such as cleaning the optical windows
or the inside of the chamber containing a substance. One or more
embodiments of the invention may also provide a modular system that
may be used in a variety of applications. For example, different
launch units may be correlated to different detect units, and such
units may be interchangeable to obtain more absorption information
quickly and efficiently.
While the invention has been described with respect to a limited
number of embodiments, those skilled in the art, having benefit of
this disclosure, will appreciate that other embodiments can be
devised which do not depart from the scope of the invention as
disclosed herein. Accordingly, the scope of the invention should be
limited only by the attached claims.
* * * * *